Possible fix for issue #409

lib/acts_as_taggable_on/tag.rb

@@ -72,13 +72,26 @@ def self.find_or_create_all_with_like_by_name(*list)
 
       return [] if list.empty?
 
-      existing_tags = Tag.named_any(list)
-
-      list.map do |tag_name|
-        comparable_tag_name = comparable_name(tag_name)
-        existing_tag = existing_tags.detect { |tag| comparable_name(tag.name) == comparable_tag_name }
+      duplicates = []
+      result = []
+      existing_tags = named_any_by_comparable_name(list)
+      list.each do |tag_name|
+        existing_tag = existing_tags[comparable_name(tag_name)]
+        if existing_tag
+          result << existing_tag
+        else
+          begin
+            result << Tag.create(:name => tag_name)
+          rescue ActiveRecord::RecordNotUnique
+            duplicates << tag_name
+          end
+        end
+      end
 
-        existing_tag || Tag.create(:name => tag_name)
+      if duplicates.empty?
+        result
+      else
+        result + Tag.named_any(duplicates)
       end
     end
 
@@ -103,8 +116,16 @@ def comparable_name(str)
         as_8bit_ascii(str).downcase
       end
 
+      # Get the list of tags and index them by the comparable_name for faster lookup
+      #
+      # @param *list [Array<Array>] Array of tag lists
+      # @return [Hash<comparable_name, tag_name>]
+      def named_any_by_comparable_name(list)
+        Hash[Tag.named_any(list).group_by{|tag| comparable_name(tag.name)}.map{|k,v| [k,v.first]}]
+      end
+
       def binary
-        /mysql/ === ActiveRecord::Base.connection_config[:adapter] ? "BINARY " : nil
+        using_mysql? ? "BINARY " : nil
       end
 
       def as_8bit_ascii(string)

lib/acts_as_taggable_on/utils.rb

@@ -15,10 +15,14 @@ def using_sqlite?
         ::ActiveRecord::Base.connection && ::ActiveRecord::Base.connection.adapter_name == 'SQLite'
       end
 
+      def using_mysql?
+        ::ActiveRecord::Base.connection && ::ActiveRecord::Base.connection.adapter_name.downcase =~ /mysql/
+      end
+
       def sha_prefix(string)
         Digest::SHA1.hexdigest("#{string}#{rand}")[0..6]
       end
-      
+
       private
       def like_operator
         using_postgresql? ? 'ILIKE' : 'LIKE'

spec/acts_as_taggable_on/tag_spec.rb

@@ -192,12 +192,12 @@
         duplicate_tag.stub(:validates_name_uniqueness?).and_return(false)
         duplicate_tag.save
         duplicate_tag.should be_persisted
-      end  
+      end
     end
 
     context "when do need unique names" do
       it "should run uniqueness validation" do
-        duplicate_tag.should_not be_valid        
+        duplicate_tag.should_not be_valid
       end
 
       it "add error to name" do

spec/acts_as_taggable_on/utils_spec.rb

@@ -18,4 +18,16 @@
       TaggableModel.send(:like_operator).should == "LIKE"
     end
   end
+
+  describe "using_mysql?" do
+    it "should return true when the adapter is mysql" do
+      TaggableModel.connection.stub(:adapter_name).and_return("MySQL2")
+      TaggableModel.using_mysql?.should be_true
+    end
+
+    it "should return false when the adapter is not mysql" do
+      TaggableModel.connection.stub(:adapter_name).and_return("PostgreSQL")
+      TaggableModel.using_mysql?.should be_false
+    end
+  end
 end